A substrate processing apparatus is used in the process of manufacturing semiconductor devices and the like to supply a treatment liquid to a surface of a substrate, such as a wafer or a liquid crystal substrate, to thereby treat the surface, and then dry the surface. In this drying process, due to the miniaturization along with the higher integration and larger capacity of recent semiconductors, for example, pattern collapse occurs around the memory cells and the gate. This is caused by structure and spacing between patterns, a surface tension of the treatment liquid, and the like.
To suppress the above-mentioned pattern collapse, there has been proposed a technology for drying a substrate with IPA (2-propanol: isopropyl alcohol) having a surface tension lower than that of ultrapure water (e.g., see Patent Document 1). Production plants employ a method for drying a substrate by replacing ultrapure water on the surface of the substrate with IPA.